Current guidelines for NSW and Victoria say that children as young as 7 are legally allowed to leave their booster seats behind and use an adult seatbelt, but trauma specialist Warwick Teague told 7 News that this is too young.

'The sash part of the seat belt will rise up across the neck, and that produces potentially life threatening injuries to the spine and the ligaments around the spine,' he said.

Also, children are being moved from rear-facing capsules to front-facing car seats too early - recommending rear-facing seats might be the way to go for children as old as 2-and-a-half.